Bolts found under engine

[lasflyer]

I have a 4 year old Beneteau with a 54HP Yanmar. It was hauled last July to replace a thru hole and at that time we found 3 loose bolts in the tray under the engine. We bolts seemed clean and not being able to locate an open bolt hole we assumed they had been left by the manufacturer and just rolled into the tray during the haulout. The engine ran normally.

Now I have found a new bolt. This time the engine seems to vibrate more at some speeds and also shuts down more quickly. The new bolt also has more grease on the threads.

The bolts are marked SA - RA and 8.8, and about 7/8 inch long.

Any ideas. Attached is a picture.

 

[kloudie1]

Dunno.. Look like cover retaining bolts, maybe oil pan retaining bolts, or a gear cover? Time to break out a mirror and carefully inspect .. They look a bit short to be coupling bolts, but I'd look there too..

 

[Don S/V ILLusion]

It should be simple to ID the possible location and use of any bolt by reviewing the exploded views of your engine in the Yanmar service manual for it. The manual has lots of important and useful information beyond simply as a service manual.

 

[LeslieTroyer]

With the wide flange looks like sheet metal to block bolts - so oil pan, valve covers, heat shields. If you get many more I’m sure the noise or oil flow will let you know exactly where their from.

Les

 

[Calif. Ted]

The 8.8 means it's a medium grade metric bolt, SA-RA is probably the bolt manufacturer. Most bolts on a Yanmar end up painted and the shiny finish reminds me of assembly bolts used by Bene. So I would suspect them to not be bolts from the engine but something bolted TO the engine, hull or surrounding woodwork. Perhaps they were removed by boatyard to gain access to thru-hull for replacement and have vibrated loose or weren't replaced.

 

[Hello Below]

Pictures of your engine room may help those that are not familiar with the Beneteau Oceanis 45. Correct me if I am wrong but given the age and manufacturer of your boat I assume you have a sail drive.

 

[lasflyer]

Thank you everyone for the input. After going over as much of the engine as I could with mirrors and all, and engine diagrams, I finally found the culprit. The loose bolts appear to be the bolts that were holding the starboard side forward engine mount to the engine block. I confirmed it by a simple comparison to the port side.

 

[Benny17441]

That could explain increased engine vibration.

 

[Tally Ho]

I found a transmission coupling bolt missing when I went to replace the shaft. Laying in the engine tray. Not nearly as clean as yours though. 4 bolts would have probably been found sooner, since the boat would move under power ;-)

Greg

 

[Calif. Ted]

A cruel but not unknown prank in fire departments was to toss a bolt or nut under the fire engine just before shift change to give the oncoming driver a mystery with his morning coffee.

 

[DayDreamer41]

Would not one have concerns for shaft alignment if the engine mount were to become loose?

 

[LeslieTroyer]

A cruel but not unknown prank in fire departments was to toss a bolt or nut under the fire engine just before shift change to give the oncoming driver a mystery with his morning coffee.

More fun is throwing clevis or cotter pins into competitors sails as they pass you (or you pass them).